Temperature‐Controlled Catalytic Growth of ZnS Nanostructures by the Evaporation of ZnS Nanopowders

ZnS nanostructures with different morphologies, sizes, and microstructures were synthesized by the evaporation of ZnS nanopowders. Based on the appearance of the as‐synthesized products, we show that substrate temperature and catalyst are the critical factors for controlling the size and the structure of various kinds of ZnS nanostructures, such as nanorods, nanowires, nanobelts, and nanosheets. Within a certain temperature range, products with a specific morphology can be obtained. Therefore, it may be possible to obtain ZnS nanostructures with a specific morphology by controlling the reaction temperature and catalyst. This represents an important step toward the design and control of nanostructures. High‐resolution electron microscopy revealed that most of the nanorods and nanowires grew along the [100] direction, whereas most of the nanobelts and nanosheets grew along [001]. Photoluminescence properties and growth mechanisms of these as‐synthesized ZnS nanostructures are discussed.     

Cathodoluminescence study of one-dimensional free-standing widegap-semiconductor nanostructures: GaN nanotubes, Si3N4 nanobelts and ZnS/Si nanowires

Luminescence properties of one-dimensional free-standing widegap-semiconductor nanostructures were characterized by means of cathodoluminescence (CL). GaN nanopipes, alpha-Si3N4 nanobelts and ZnS/Si nanowires were fabricated by a catalyst-free method, namely grown in an induction furnace from powders. After the observation of morphology by scanning electron microscopy as well as the confirmation of their crystal structures by transmission electron microscopy, their CL spectra and images were observed. The CL spectra mapping as well as the monochromatic CL imaging revealed the variation of the luminescence spectra of different nanowires as well as that along a single wire. These results revealed the optical features of nanostructures.     

Tunable Synthesis of Various Wurtzite ZnS Architectural Structures and Their Photocatalytic Properties

Semiconductor ZnS with novel and complex 3D architectures such as nanorods (or nanowires) networks, urchinlike nanosturctures, nearly monodisperse nanospheres self‐assembled from nanorods and 1D nanostructures (rods and wires) had been synthesized in a binary solution by controlling the reaction conditions, such as the volume ratio of the mixed solvents and the reaction temperature. The morphology of ZnS changed from 3D architectural structures to 1D rodlike (or wirelike) shape when the temperature was increased from 160 to 200–240 °C. The possible growth mechanisms for the formation of nanospheres self‐assembled from nanorods are tentatively discussed according to the experimental results. The photocatalytic activity of various ZnS nanostructures has been tested by degradation of acid fuchsine under infrared light compared to that of commercial ZnS powders under infrared‐light irradiation and commercial TiO₂ powders under UV‐light irradiation, indicating that the as‐obtained ZnS nanostructures exhibit excellent photocatalytic activity for degradation of acid fuchsine.     

ZnS微球的制备及吸光性能研究

采用溶剂热法,以醋酸锌和硫脲为原料,去离子水和无水乙醇的混合溶液为反应介质制备了ZnS微球。利用XRD、SEM、UV-Vis吸收光谱探讨了反应温度和时间对产物晶型、颗粒形貌以及吸光性能的影响。结果表明:ZnS微球的晶型和形貌对反应温度比较敏感,反应时间对晶体的结晶度和吸光率影响较大。采用溶剂热法的最佳合成温度为150℃左右,反应时间为12 h;该条件下生成的ZnS微球物相较为纯净、结晶完全,且分散性良好,带隙约为3.3 eV。     

From Mesostructured Wurtzite ZnS‐Nanowire/Amine Nanocomposites to ZnS Nanowires Exhibiting Quantum Size Effects: A Mild‐Solution Chemistry Approach

Mesostructured wurtzite ZnS‐nanowire‐bundle/amine nanocomposites displaying remarkable quantum size effects are synthesized by using a mild‐solution reaction using different amines, such as n‐butylamine, ethylamine, and tetraethylenepentamine, Zn(NO₃)₂·6 H₂O, and CS(NH₂)₂ or Na₂S·9 H₂O as the precursors at temperatures ranging from room temperature to 180 °C. A possible mechanism for the shape‐controlled growth of ZnS nanowires and nanocomposites is proposed. Increasing the reaction temperature or dispersing the composite in acetic acid or NaOH solution leads to the destruction of the periodic structure and the formation of individual wurtzite nanowires and their aggregates. The nanowire/amine composites and individual wurtzite nanowires both display obvious quantum size effects. Strong band‐edge emission is observed for the wurtzite ZnS nanowires after removal of the amine. The optical properties of these nanocomposites and nanowires are strongly related to the preparation conditions and can be finely tuned. This technique provides a unique approach for fabricating highly oriented wurtzite ZnS semiconductor nanowires, and can potentially be extended to other semiconducting systems.     

Synthesis,characterization, and measurement of structural,optical, and phtotoluminescent properties of zinc sulfide quantum dots

A facile and rapid microwave irradiation method was developed to prepare ZnS nanoparticles (NPs) using a set of ionic liquids (ILs) based on the bis(trifluoromethylsulfonyl) imide anion and different cations of 1-alkyl-3-methyl-imidazolium. The phases, structures, and optical absorption properties of the NPs were determined in depth with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, UV–vis absorption spectroscopy (UV–vis), diffuse reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL). The average crystallite size of the ZnS NPs calculated from the XRD pattern was of the order of 2.8 nm which exhibits cubic zinc blende structure. The energy band gap measurements of NPs were carried out by UV and DRS. The results revealed that the ZnS NPs exhibit strong quantum confinement effect. The optical band gap energy increases significantly compared with those of the bulk ZnS. The refractive indices for different ZnS nanosamples and different concentrations of ZnS NPs for a typical sample suspended in deionized water were also measured.     

One‐Step Preparation of Coaxial CdS–ZnS and Cd1–xZnxS–ZnS Nanowires

Preparation of coaxial (core–shell) CdS–ZnS and Cd_1–xZn_xS–ZnS nanowires has been achieved via a one‐step metal–organic chemical vapor deposition (MOCVD) process with co‐fed single‐source precursors of CdS and ZnS. Single‐source precursors of CdS and ZnS of sufficient reactivity difference were prepared and paired up to form coaxial nanostructures in a one‐step process. The sequential growth of ZnS on CdS nanowires was also conducted to demonstrate the necessity and advantages of the precursor co‐feeding practice for the formation of well‐defined coaxial nanostructures. The coaxial nanostructure was characterized and confirmed by high‐resolution transmission electron microscopy and corresponding energy dispersive X‐ray spectrometry analyses. The photoluminescence efficiencies of the resulting coaxial CdS–ZnS and Cd_1–xZn_xS–ZnS nanowires were significantly enhanced compared to those of the plain CdS and plain Cd_1–xZn_xS nanowires, respectively, owing to the effective passivation of the surface electronic states of the core materials by the ZnS shell.     

Halide‐Transport Chemical Vapor Deposition of Luminescent ZnS:Mn2+ One‐Dimensional Nanostructures

ZnS:M²⁺ (M = Mn, Co, or Cu) single‐crystal one‐dimensional nanostructures have been prepared via a simple halide‐transport chemical vapor deposition (HTCVD) process at a relatively low temperature. The obvious phase transition suggests that doping with Mn favors the formation of the hexagonal phase at a relative low temperature. The strong photoluminescence from blue to green and the yellow–orange emission, which was caused by the doping of various elements in ZnS nanowires and nanobelts, suggests possible applications of the one‐dimensional nanostructures in nanoscale optoelectronic devices.     

微波用于抑制光刻胶纳米线条倒伏的研究

针对半导体工艺中去离子水的表面张力导致显影干燥过程中光刻胶纳米线条容易发生倒伏的问题,采用了微波干燥方法,以抑制光刻胶纳米线条倒伏。利用微波的热效应和非热效应,降低去离子水的表面张力,使光刻胶纳米线条上的去离子水均匀、快速地蒸发,有效抑制了光刻胶纳米线条的倒伏。与氮气干燥处理的传统方法相比,该方法能使高130 nm、宽15 nm的光刻胶纳米线条不发生倒伏,效果明显。这表明,该方法是可行和有效的。     

Study of capping agent effect on the structural,optical and photocatalytic properties of zinc sulfide quantum dots

In this work, the effect of capping agent type on the structural, optical and photocatalytic properties of pure zinc sulfide (ZnS) quantum dots (QDs) has been investigated. ZnS QDs were prepared by a simple, fast and water based chemical precipitation method, in the presence of various capping agents including 2-mercaptoethanol, thiourea, and l-cysteine. The obtained QDs have been characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), and UV–visible absorption spectroscopy. The results revealed that the optical absorption band of ZnS nanostructures varied by capping agents. In the photocatalytic investigations, the prepared ZnS QDs were applied for the photodecolorization of crystal violet (CV) as a model molecule. Influence of affecting parameters on the decolorization efficiency of the capped ZnS QDs was studied and optimized. The results indicated that the prepared QDs can effectively remove different concentrations of CV dye at alkaline pH, in the presence of low concentrations of QDs. According to the photocatalytic results, the presented method can be considered as a green, quick and efficient strategy for photobleaching of organic pollutants based on the high performance photocatalytic behavior of ZnS QDs capped by different capping agents.     

花状纳米结构ZnS:Cu的制备与光学性质研究

采用水热法合成了具有花状纳米结构的ZnS:Cu粉末.利用X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)和荧光光谱仪研究了在不同正硅酸四乙酯(TEOS)含量的条件下制备的样品的物相、形貌与光致发光(PL)性质.测试结果表明:制备的ZnS:Cu样品都具有立方相闪锌矿结构;由于TEOS分子...     

Cathodoluminescence Modulation of ZnS Nanostructures by Morphology,Doping, and Temperature

Spatially and spectrally resolved cathodoluminescence (CL) is one of the most effective methods to explore the optical properties of a nanomaterials and reveals the spatial distribution as well as the correlation between the luminescence and the sample morphology and microstructure. Here, CL modulation of ZnS nanostructures by controlled morphologies, Fe/Mn doping, and measurement temperature is demonstrated. High quality ZnS nanobelts and nanorods are synthesized on an Au‐coated Si substrate and an Au‐coated GaAs substrate via a facile thermal evaporation route. A room‐temperature sharp ultraviolet (UV) lasing‐like peak in various ZnS is achieved. The main UV luminescence peaks appear at wavelengths between 330 and 338 nm. The low temperature (32 K) CL spectrum consists of a narrow and strong UV peak centered at 330 nm and two broad, low‐intensity peaks in the visible region (514 and 610 nm). Temperature‐dependent CL from such single‐crystalline ZnS nanobelts in the temperature range of 32 to 296 K reveals two UV peaks at 3.757 and 3.646 eV. The effects of Fe doping and Fe/Mn co‐doping on the CL property of ZnS nanobelts are further investigated. These results imply that ZnS nanostructures can be used for potential luminescent materials as well as short‐wavelength nanolaser light sources.     

In-situ deposition of zinc oxide nanowires onto UV-cured chitin derivatives and their antibacterial properties

ZnO nanowires were synthesized on UV-cured chitin film by using a hydrothermal method. Structural and optical characterization showed that one dimensional nanowires can be produced on the UV-cured chitin film. The morphological analysis indicated that nanowires structures can be obtained at about 30 nm radius and 10 µm length. Surface morphology of the ZnO coated UV-cured chitin film was also investigated and a three-dimensional surface profile and high surface roughness were obtained. X-ray diffraction analysis of the film showed large and pure crystals of ZnO nanowires with wurtzite structure and UV–visible absorbance spectrum indicated that ZnO nanowires have 3.39 eV band-gap energy and nanostructures have very good transparency of about 80% in blue region. Also ZnO coated film was tested for its biocidal action against Gram positive Staphylococcus aureus using an agar plate method. This newly developed nano-biomaterial exhibited a strong antibacterial effect.     

ZnSe纳米材料及界面的制备与表征

利用热蒸发法对ZnSe纳米材料的相控合成进行了研究,制备了多种具有稳定闪锌矿和亚稳纤锌矿结构的ZnSe纳米材料,如ZnSe纳米线、纳米圈、纳米轮及三晶纳米带。同时,在相控合成基础上,通过改变管式炉内反应压强获得了几种同质与异质界面。利用多种透射电子显微学手段对合成的ZnSe纳米材料及相关同质与异质界面进行了深入表征,并对ZnSe纳米材料的生长机理进行了探讨。     

Enhanced photoluminescence properties of ZnS:Cu2+ nanoparticles using PMMA and CTAB surfactants

ZnS nanoparticles with Cu²⁺ doping have been synthesized at 80 °C through a soft chemical route, namely the chemical co-precipitation method at air atmosphere. The water soluble PMMA and CTAB were used as capping agents. The nanostructures of the synthesized nanoparticles have been analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier transform infrared spectrometer (FT-IR), UV–vis and fluorescence spectrophotometer. The sizes of as-prepared nanoparticles are found to be below 3.4–5.2 nm range. Room temperature photoluminescence (PL) spectrum of the undoped sample exhibits emission in the blue region with multiple peaks under UV excitation. On the other hand, in the Cu²⁺ doped ZnS samples enhanced visible light emissions with emission intensities of ∼2 times larger than that of the undoped sample are observed for CTAB capped sample. The phase changes were observed in different temperatures by TG-DTA.     

氧化物缓冲层制备Si(111)基GaN纳米线

采用氧化物缓冲层,通过射频磁控溅射系统依次在n型Si(111)衬底上沉积Ga2O3/ZnO(Ga2O3/MgO)薄膜,然后将薄膜于950℃氨化合成GaN纳米结构,氨化时间为15min。采用X射线衍射(XRD)、傅里叶红外吸收谱(FTIR)和高分辨透射电镜(HRTEM)对样品的结构进行了分析,结果显示两种缓冲层下制备的样品均为六方纤锌矿单晶GaN纳米结构,且缓冲层的取向对纳米线的生长方向有很大影响;采用扫描电镜(SEM)对样品的形貌进行了测试,发现纳米线表面光滑,长度可达几十微米,表明采用氧化物缓冲层制备了高质量的GaN线。同时对GaN纳米线的生长机理进行了简单讨论。     

Synthesis,characterization and optical properties of mercury sulfides and zinc sulfides using single-source precursor

HgS and ZnS nanostructures were prepared by using two different methods. HgS nanodendrites and ZnS nanospheres were synthesized via hydrothermal decomposition of [M(TSC)₂]Cl₂ complex (M=Hg, Zn and TSC=thiosemicarbazide), without any surfactant. And using oleylamine (C₁₈H₃₇N) and TPP (C₁₈H₁₅P) as surfactant, HgS nanoparticles with an average diameter of approximately 20–40 nm were synthesized by thermal decomposition of the [Hg(TSC)₂]Cl₂, whereas the coalesced particles and bulk structures were formed by thermal decomposition of [Zn(TSC)₂]Cl₂. To study the crystalline structure, size, morphology and composition of the products, characterization techniques including X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectroscopy were employed. Ultraviolet visible (UV–vis) absorption and photoluminescence (PL) spectroscopy exhibited optical properties of nanostructures.     

Integration of SiC-1D nanostructures into nano-field effect transistors

We report on the integration and the electrical transport properties of silicon carbide-based one-dimensional nanostructures into field effect transistors. Different kinds of SiC-based 1D nanostructures have been used: 3C– and 4H–SiC nanowires obtained by a plasma etching process, Si–SiC core–shell nanowires and SiC nanotubes both obtained by a carburization route of silicon nanowires.     

Synthesis of GaN nanowires and nanorods via self-growth mode control

The synthesis of hexagonal wurzite one-dimensional (1D) GaN nanostructures on c-Al₂O₃ substrates was investigated using a thermal chemical vapor deposition (CVD) process. The diameter of the GaN nanostructures was controlled by varying the growth time using a mixture of GaN powder and Ga metal with the ammonia gas reaction. The morphologies of the GaN nanowires and nanorods were confirmed by field emission scanning electron microscopy. The micro-Raman spectroscopy and X-ray scattering measurements indicated that the GaN nanostructures had a hexagonal wurzite structure without any oxide phases. We investigated the difference in the structural properties between the GaN nanowires and nanorods. Deep-level emission bands were not observed in cathodoluminescence measurements from either the GaN nanowires or nanorods, indicating the incorporation of low-level impurities into our 1D GaN nanostructures.     

1D Tellurium Nanostructures: Photothermally Assisted Morphology‐Controlled Synthesis and Applications in Preparing Functional Nanoscale Materials

A facile visible‐light‐assisted solution‐phase approach has been successfully developed to synthesize trigonal Te 1D nanostructures. By varying the relative amount of H₂TeO₃ and water‐soluble polymers, wirelike, beltlike, tubular Te, and Te nanoparticle‐joined 1D aggregates, as well as a novel thorny 1D assembly of Te nanothreads can be synthesized on a large scale. The diameter of the Te nanowires can be modulated by controlling the nucleation and growth process through modulation of the pH value of the reaction mixture. It is believed that the light irradiation and thermal effect play a significant role in this photothermally assisted technique. We have shown that the Te nanowires can be used as a template to prepare Pt–Te nanochains, where the composition of Pt in the Pt–Te 1D products can be modulated by adjusting the ratio of the Te nanowires and Pt salts. Preliminary optical investigations reveal that blue–violet emission of Te nanowires can be enhanced by the formation of defects or dislocations in the Te region through the galvanic replacement reaction between Te nanowires and H₂PtCl₆. In addition, we demonstrate that Te 1D nanostructures can be utilized to prepare Te at carbon‐rich nanocables and carbonaceous nanotubes. Te–Pt at carbon‐rich nanocables can also be fabricated using Te–Pt nanochains as the template. These Pt–Te nanochains and carbonaceous nanostructures are expected to find wide applications in electrochemistry, catalysis, fuel cells, sensors, and other fields. Furthermore, the successful preparation of Te 1D nanostructures with abundant shapes, Pt–Te nanochains, and their carbonaceous composite nanomaterials will offer great opportunities to explore the dependence of novel properties of nanomaterials on their morphology and composition, regulate the photoconductivity of semiconductors, and also be essential for the manufacture of potential optoelectronic devices.